Adhesive film production apparatus and reel bodies

ABSTRACT

Provided is an adhesive film production apparatus for producing an adhesive film having an adhesive layer on a base material layer, the adhesive film production apparatus including: a feeding roller that continuously feeds a raw film of the adhesive film; a cutting part that cuts the raw film of the adhesive film into a plurality of adhesive films having predetermined widths; and a plurality of winding cores that wind each of the plurality of adhesive films, wherein each of the plurality of winding cores has a width larger than a width of the adhesive film as an object of winding.

TECHNICAL FIELD

The present disclosure relates to an adhesive film production apparatusand a reel body.

BACKGROUND ART

Conventional semiconductor packages have a structure which includes asemiconductor element adhered onto a die pad, and a lead frame joined tothe semiconductor element with a wire, and in which the entirety exceptfor outer leads for external connection is sealed with a resin. As thedemand for density increase, area reduction, thickness reduction, andthe like of semiconductor packages has increased in recent years, forexample, semiconductor packages having a structure in which only onesurface (semiconductor element side) of a package is sealed, as in thecase of a QFN (Quad Flat Non-leaded) package, have been developed.

In a semiconductor package having a structure in which only one surfaceof the package is sealed, since a lead frame is not protruding throughthe sealing resin, area reduction and thickness reduction of the packagecan be attempted. However, there may occur a defect that the sealingresin wraps around the back surface of the lead frame at the time ofsealing. As a method for preventing such a defect, for example, as inthe case of Patent Literature 1, there is a method of sticking anadhesive film as a temporary protective film to the back surface of thelead frame. In this method, sealing of a semiconductor element isperformed in a state in which the back surface of a lead frame istemporarily protected with an adhesive film, and subsequently theadhesive film is peeled off from the back surface of the lead frame.

CITATION LIST Patent Literature

Patent Literature 1: International Publication WO 2001/035460

SUMMARY OF INVENTION Technical Problem

An adhesive film that is used as a temporary protective film is formedby, for example, cutting a raw film that is continuously paid out from afeeding roller to an arbitrary width. Each of the adhesive films cut outinto each width is wound around a winding core and is handled as a reelbody. At the site of use of the adhesive film, the adhesive film isdrawn out from the reel body, and sticking of the adhesive film to theback surface of a lead frame is performed.

For such an adhesive film, adhesive films of various widths are usedaccording to the shape of the lead frame as an object of sticking. Forthis reason, when the width of the winding core is varied from case tocase according to the width of the adhesive film to be wound, it isconceivable that the setting of the winding core in an adhesive filmproduction apparatus becomes complicated. Furthermore, it is necessaryto prepare a large number of winding cores having different widths, andthere is concern that the production cost for reel bodies may beincreased.

The present disclosure was achieved in order to solve theabove-described problems, and it is an object of the present disclosureto provide an adhesive film production apparatus that can cope with thewinding of adhesive films having different widths and can reduce theproduction cost of reel bodies, and a reel body.

Solution to Problem

An adhesive film production apparatus according to an aspect of thepresent disclosure is an adhesive film production apparatus forproducing an adhesive film having an adhesive layer on a base materiallayer, the adhesive film production apparatus including a feeding rollerfor continuously feeding out a raw film of the adhesive film; a cuttingpart for cutting the raw film of the adhesive film into a plurality ofadhesive films having predetermined widths; and a plurality of windingcores for winding each of the plurality of adhesive films, wherein eachof the plurality of winding cores has a width larger than a width of theadhesive film as an object of winding.

In this adhesive film production apparatus, each of the plurality ofwinding cores for winding an adhesive film has a width larger than awidth of the adhesive film as an object of winding. As a result, windingof an adhesive film having a width smaller than the width of the windingcore can be performed by using winding cores having the same width.Therefore, in this adhesive film production apparatus, it is possible toreduce the types of the winding core to be prepared, and the productioncost for reel bodies can be reduced. Furthermore, since the edge part ofthe winding core protrudes from the adhesive film as an object ofwinding, when an adhesive film wound around the winding core is used,alignment of the adhesive film is made easier by utilizing theprotruding portion of the winding core.

Each of the plurality of winding cores may be disposed such that theedge part of the winding core protrudes only on one side in an axialdirection from the adhesive film as an object of winding. In this case,when the adhesive film wound around the winding core is used, alignmentof the adhesive film is made easier.

A reel body according to an aspect of the present disclosure is a reelbody obtained by winding an adhesive film having an adhesive layer on abase material layer around a winding core, and the winding core has awidth larger than a width of the adhesive film.

In this reel body, a width of the winding core is larger than a width ofthe adhesive film. As a result, winding of an adhesive film having awidth smaller than that of the winding core can be performed by usingwinding cores having the same width. Therefore, in this reel body, it ispossible to reduce the number of types of the winding cores to beprepared, and the production cost can be reduced. Furthermore, since theedge part of the winding core protrudes from the adhesive film as anobject of winding, when an adhesive film wound around the winding coreis used, alignment of the adhesive film is made easier by utilizing theprotruding portion of the winding core.

An edge part of the winding core may protrude only on one side in anaxial direction from a rolled body of the adhesive film. In this case,when an adhesive film wound around the winding core is used, alignmentof the adhesive film is made much easier.

Edge parts of the winding core may protrude on both sides in an axialdirection from side surfaces of the rolled body of the adhesive film,and an amount of protrusion on one side in the axial direction may belarger than an amount of protrusion on the other side. In this case,when an adhesive film wound around the winding core is used, alignmentof the adhesive film is made much easier.

Advantageous Effects of Invention

According to the present disclosure, winding of adhesive films havingdifferent widths can be coped with, and the production cost for reelbodies can be reduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional view illustrating an embodiment ofan adhesive film.

FIG. 2 is a schematic cross-sectional view illustrating anotherembodiment of the adhesive film.

FIG. 3 is a schematic perspective view illustrating an embodiment of anadhesive film production apparatus.

FIG. 4 is a schematic cross-sectional view illustrating a winding stateof a raw film of the adhesive film in a feeding roller.

FIG. 5 is a schematic cross-sectional view illustrating a conveyancestate of the adhesive film from a cutting part toward a winding core.

FIG. 6 is a plan view illustrating a winding state of the adhesive filmon the winding core.

FIG. 7 is a schematic perspective view illustrating an embodiment of amethod for producing an adhesive film.

FIG. 8 is a schematic perspective view illustrating another embodimentof an adhesive film production apparatus.

DESCRIPTION OF EMBODIMENTS

In the following description, suitable embodiments of an adhesive filmproduction apparatus and a reel body according to an aspect of thepresent disclosure will be described in detail with reference to thedrawings.

[Adhesive Film]

First, the configuration of an adhesive film produced by an adhesivefilm production apparatus will be described. FIG. 1 is a schematiccross-sectional view illustrating an embodiment of the adhesive film.The adhesive film 1 shown in FIG. 1 is, for example, a film that is usedfor temporary protection of a lead frame in a sealing step of sealing asemiconductor element mounted on the lead frame. In the sealing step,the adhesive film 1 is stuck to the back surface of the lead frame(surface on the opposite side of the surface where the semiconductorelement is formed) and temporarily protects the lead frame while asealing layer for sealing the semiconductor element is formed. Theadhesive film 1 is peeled off from the back surface of the lead frameafter the sealing step is completed.

The adhesive film 1 is handled, for example, in a reel body state ofbeing wound around a winding core 14 (see FIG. 3 ). The adhesive film 1may be handled in a state in which the reel body is housed in apackaging bag. In this case, a single reel body may be housed in thepackaging bag, or a plurality of reel bodies may be housed in thepackaging bag. The packaging bag may be formed by using a resin film ormay be formed by using a composite resin film having an aluminum layer.Specific examples of the packaging bag include a bag made of analuminum-coated plastic. Examples of the material of the resin filminclude plastic such as polyethylene, polyester, vinyl chloride, andpolyethylene terephthalate. The reel body may be housed in the packagingbag, for example, in a vacuum packed state. In the packaging bag, adesiccant may be housed together with the reel body. Regarding thedesiccant, for example, silica gel may be mentioned. The package may befurther wrapped with a cushioning material. The package may be housedin, for example, a packing box such as corrugated cardboard.

As shown in FIG. 1 , the adhesive film 1 is configured to have twolayers composed of a base material layer 2 and an adhesive layer 3provided on one surface side of the base material layer 2. The width ofthe adhesive film 1 is, for example, 50 mm or more. The width of theadhesive film 1 may be 100 mm or more or may be 200 mm or more. Thewidth of the adhesive film 1 may be 600 mm or less. The width of theadhesive film 1 may be, for example, 50 mm or more and 600 mm or less,may be 100 mm or more and 600 mm or less, or may be 200 mm or more and600 mm or less.

The coefficient of linear expansion at 30° C. to 200° C. on the in-planedirection of the adhesive film 1 is, for example, 16 ppm/° C. or greaterand 20 ppm/° C. or less. The in-plane direction may be, for example,either the MD (Machine Direction) direction or the TD (TransverseDirection) direction. The MD direction is usually the longitudinaldirection of the adhesive film 1. The TD direction is a direction (widthdirection) orthogonal to the MD direction. The measurement of thecoefficient of linear expansion can be measured by means of athermomechanical analysis apparatus (for example, manufactured by SeikoInstruments Inc.: SSC5200). The coefficient of linear expansion at 30°C. to 200° C. in the in-plane direction of the adhesive film 1 can beadjusted by, for example, changing the thickness of the adhesive layer3.

The elastic modulus at 30° C. of the adhesive film 1 is, for example, 9GPa or less. The elastic modulus at 30° C. of the adhesive film 1 may be8 GPa or less or may be 7 GPa or less. The elastic modulus at 30° C. ofthe adhesive film 1 may be 4 GPa or greater or may be 5 GPa or greater.The elastic modulus at 30° C. of the adhesive film 1 can be measured byusing a dynamic viscoelasticity measuring apparatus (for example,manufactured by UBM: Rheogel-E4000). In this case, a specimen obtainedby cutting the adhesive film 1 into a size of, for example, 4 mm×30 mmis mounted on a dynamic viscoelasticity measuring apparatus at adistance between chucks of 20 mm. Then, the elastic modulus at 30° C. ofthe adhesive film 1 can be determined by measuring the tensile modulusof the specimen under the conditions of sine waves, a temperature rangeof 30° C. (constant), and a frequency of 10 Hz.

The base material layer 2 is composed of a material having heatresistance against the heat in each step of a step of forming anadhesive layer 3, a step of assembling a semiconductor package, and thelike. Such a material may be, for example, at least one polymer selectedfrom the group consisting of an aromatic polyimide, an aromaticpolyamide, an aromatic polyamideimide, an aromatic polysulfone, anaromatic polyethersulfone, polyphenylene sulfide, an aromatic polyetherketone, polyallylate, an aromatic polyether ether ketone, andpolyethylene naphthalate.

From the viewpoint of enhancing the heat resistance, the glasstransition temperature of the base material layer 2 may be 200° C. orhigher or may be 250° C. or higher. As a result, in the steps where heatis applied, that is, a step of adhering a semiconductor element to a diepad, a wire bonding step, a sealing step, and a step of tearing off thetemporary protective film from a molded body, softening of the basematerial layer 2 is suppressed, and an enhancement of the operationefficiency can be promoted. Furthermore, the elastic modulus at 230° C.of the base material layer 2 is higher than the elastic modulus at 230°C. of the adhesive layer 3 (which will be described below).

It is preferable that the base material layer 2 has sufficient closeadhesiveness to the adhesive layer 3. When the base material layer 2 hassufficient close adhesiveness to the adhesive layer 3, for example, atthe time of tearing off the adhesive film 1 from the lead frame and thesealing material at a temperature of 100° C. to 300° C., the occurrenceof peeling at the interface between the adhesive layer 3 and the basematerial layer 2 can be suppressed. As a result, the resin remaining onthe lead frame and the sealing material can be suppressed.

From the viewpoint of sufficiently having both the heat resistance andthe close adhesiveness to the adhesive layer 3, the base material layer2 may be composed of polyimide. The coefficient of linear expansion at30° C. to 200° C. of the base material layer 2 based on polyimide may be3.0×10⁻⁵/° C. or less, may be 2.5×10⁻⁵° C. or less, or may be 2.0×10⁻⁵/°C. or less. The heat shrinkage rate of the base material layer 2 at thetime of heating at 200° C. for 2 hours may be 0.15% or less, may be 0.1%or less, or may be 0.05% or less.

The material that constitutes the base material layer 2 is not limitedto the above-described resin and can also be selected from the groupconsisting of copper, aluminum, stainless steel, and nickel. When thebase material layer 2 is composed of these metals, it is possible tobring the coefficient of linear expansion of the adhesive film 1 closerto the coefficient of linear expansion of the lead frame, and thewarpage of the lead frame at the time of sticking the adhesive film 1 tothe lead frame can be suitably reduced.

The base material layer 2 may be subjected to a surface treatment.Examples of the type of the surface treatment include chemicaltreatments such as an alkali treatment and a silane coupling treatment;physical treatments such as a sand mat treatment; a plasma treatment,and a corona treatment. By applying a surface treatment, the closeadhesiveness to the adhesive layer 3 can be more sufficiently increased.

From the viewpoint of reducing the warpage of a lead frame when theadhesive film 1 is stuck to the lead frame, the thickness of the basematerial layer 2 may be, for example, 100 μm or less, may be 50 μm orless, or may be 25 μm or less. The thickness of the base material layer2 may be 5 μm or more or may be 10 μm or more.

The adhesive layer 3 is composed of, for example, a thermoplastic resinhaving an amide group (—NHCO—), an ester group (—CO—O—), an imide group(—NR₂, provided that each R is —CO—), an ether group (—O—), or a sulfonegroup (—SO₂—). These resins may be thermoplastic resins having an amidegroup, an ester group, an imide group, or an ether group. Specifically,examples of such a thermoplastic resin include an aromatic polyamide, anaromatic polyester, an aromatic polyimide, an aromatic polyamideimide,an aromatic polyether, an aromatic polyetheramideimide, an aromaticpolyetheramide, an aromatic polyesterimide, and an aromaticpolyetherimide. From the viewpoints of heat resistance and adhesiveness,the thermoplastic resin may be at least one resin selected from thegroup consisting of an aromatic polyetheramideimide, an aromaticpolyetherimide, and an aromatic polyetheramide.

The above-described resins can all be produced by subjecting a basecomponent such as an aromatic diamine or a bisphenol and an acidcomponent such as a dicarboxylic acid, a tricarboxylic acid, atetracarboxylic acid, or an aromatic chloride, or reactive derivativesof these to polycondensation. That is, the production of theabove-described resins can be carried out by a conventional method thatis used for the reaction between an amine and an acid, and there are noparticular limitations in the general conditions and the like. For apolycondensation reaction between an aromatic dicarboxylic acid, anaromatic tricarboxylic acid, or reactive derivatives of these and adiamine as well, a conventional method is used.

Regarding the base component used for the synthesis of an aromaticpolyetherimide, an aromatic polyetheramideimide, and an aromaticpolyetheramide, for example, aromatic diamines having an ether group,such as 2,2-bis[4-(4-aminophenoxy)phenyl]propane,bis[4-(4-aminophenoxy)phenyl]sulfone, 4,4′-diaminodiphenyl ether,bis[4-(4-aminophenoxy)phenyl] ether, and2,2-bis[4-(4-aminophenoxy)]hexafluoropropane; aromatic diamines that donot have an ether group, such as4,4′-methylenebis(2,6-diisopropylamine); siloxanediamines such as1,3-bis(3-aminopropyl)-tetramethyldisiloxane; and α,ω-diaminoalkanessuch as 1,12-diaminododecane and 1,6-diaminohexane, can be used.

In the total amount of the base component, the above-described aromaticdiamine having an ether group may be used in an amount of 40 mol % to100 mol % or 50 mol % to 97 mol %, and at least one selected from thearomatic diamine that does not have an ether group, a siloxanediamine,and α,ω-diaminoalkane may be used in an amount of 0 mol % to 60 mol % or3 mol % to 50 mol %. Specific examples of the base component include:(1) a base component composed of 60 mol % to 89 mol % or 68 mol % to 82mol % of an aromatic diamine having an ether group, 1 mol % to 10 mol %or 3 mol % to 7 mol % of a siloxanediamine, and 10 mol % to 30 mol % or15 mol % to 25 mol % of an α,ω-diaminoalkane; (2) a base componentcomposed of 90 mol % to 99 mol % or 93 mol % to 97 mol % of an aromaticdiamine having an ether group and 1 mol % to 10 mol % or 3 mol % to 7mol % of a siloxanediamine; and (3) a base component composed of 40 mol% to 70 mol % or 45 mol % to 60 mol % of an aromatic diamine having anether group and 30 mol % to 60 mol % or 40 mol % to 55 mol % of anaromatic diamine that does not include an ether group.

Examples of the acid component used for the synthesis of the aromaticpolyetherimide, aromatic polyetheramideimide, and aromaticpolyetheramide include: (A) mononuclear aromatic tricarboxylic acidanhydrides and mononuclear aromatic tetracarboxylic acid dianhydrides,such as trimellitic anhydride, a reactive derivative of trimelliticanhydride such as trimellitic anhydride chloride, and pyromelliticdianhydride; (B) polynuclear aromatic tetracarboxylic acid dianhydridessuch as bisphenol A bistrimellitate dianhydride, oxydiphthalicanhydride; and (C) aromatic dicarboxylic acids such as terephthalicacid, isophthalic acid, terephthalic acid chloride, and a reactivederivative of phthalic acid such as isophthalic acid chloride. Amongthese, an aromatic polyetheramideimide obtainable by reacting 0.95 to1.05 mol or 0.98 to 1.02 mol of the above-described acid component (A)per 1 mol of the above-described base component (1) or (2), and anaromatic polyetherimide obtainable by reacting 0.95 to 1.05 mol or 0.98to 1.02 mol of the above-described acid component (B) per 1 mol of theabove-described base component (3), can be used.

The adhesive layer 3 may contain a component other than theabove-described resin. Examples of the other component include fillerssuch as a ceramic powder, a glass powder, a silver powder, a copperpowder, resin particles, and rubber particles; an oxidation inhibitor;and a coupling agent. When the adhesive layer 3 contains a filler as theother component, the content of the filler may be 1 to 30 parts by massor may be 5 to 15 parts by mass, with respect to 100 parts by mass ofthe resin.

Regarding the coupling agent, for example, vinylsilane, epoxysilane,aminosilane, mercaptosilane, a titanate, an aluminum chelate, azircoaluminuate, and the like can be used. The coupling agent may be asilane coupling agent. Regarding the silane coupling agent, couplingagents having organic reactive groups at the ends ofvinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,γ-glycidoxypropyltrimethoxysilane,γ-glycidoxypropylmethyldiethoxysilane,N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane,γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane,γ-mercaptopropyltrimethoxysilane, and the like, and among these, anepoxysilane coupling agent having an epoxy group can be used.

The organic reactive group is a functional group such as an epoxy group,a vinyl group, an amino group, or a mercapto group. The addition of asilane coupling agent provides an effect of enhancing the closeadhesiveness of the adhesive layer 3 to the base material layer 2 andsuppressing the occurrence of peeling at the interface between the basematerial layer 2 and the adhesive layer 3 at the time of peeling at atemperature of 100 to 300° C. When the adhesive layer 3 contains acoupling agent, the content of the coupling agent may be 1 to 15 partsby mass or may be 2 to 10 parts by mass with respect to 100 parts bymass of the resin.

The thickness of the adhesive layer 3 is, for example, 20 μm or less.The thickness of the adhesive layer 3 may be 18 μm or less, 16 μm orless, 14 μm or less, 12 μm or less, 10 μm or less, 9 μm or less, or 8 μmor less. The thickness of the adhesive layer 3 is, for example, 1 μm ormore. The thickness of the adhesive layer 3 may be 2 μm or more, 3 μm ormore, 4 μm or more, 5 μm or more, 6 μm or more, 7 μm or more, or 8 μm ormore. The thickness of the adhesive layer 3 may be 1 μm or more and 20μm or less, may be 1 μm or more and 15 μm or less, or may be 1 μm ormore and 8 μm or less.

When the thickness of the adhesive layer 3 is 1 μm or more, sufficientadhesiveness can be secured, and at the same time, fall-off of thesealing material at the time of sealing can be suppressed. When thethickness of the adhesive layer 3 is 20 μm or less, the overall layerthickness of the adhesive film 1 is suppressed, the cost is suppressed,and in addition to that, the generation of voids at the time ofperforming a heat treatment at 300° C. or higher can be suppressed.Furthermore, when the thickness of the adhesive layer 3 is 20 μm orless, an increase in the wettability at the time of a heat treatment canbe suppressed. As a result, the adhesive layer 3 sticking to the leadframe with an excessive adhesive strength can be suppressed, andpeelability can be secured.

The ratio of the thickness of the adhesive layer 3 to the thickness ofthe base material layer 2 is, for example, 0.2 or less. The ratio of thethickness of the adhesive layer 3 to the thickness of the base materiallayer 2 may be 0.1 or less or may be 0.05 or less. As a result, thewarpage caused by the volume reduction at the time of solvent removalafter application of the adhesive layer 3 on the base material layer 2is suppressed, and the workability at the time of sticking the adhesivefilm 1 to the lead frame can be enhanced.

The glass transition temperature (Tg) of the adhesive layer 3 is higherthan normal temperature (for example, 25° C.). The glass transitiontemperature (Tg) of the adhesive layer 3 may be, for example, 100° C. orhigher or may be 150° C. or higher. The glass transition temperature ofthe adhesive layer 3 may be, for example, 300° C. or lower or may be250° C. or lower. In a case where the glass transition temperature ofthe adhesive layer 3 is 100° C. or higher, when the adhesive film 1 ispeeled off from the lead frame and the sealing material, peeling at theinterface between the base material layer 2 and the adhesive layer 3 issuppressed, and the cohesive failure of the adhesive layer 3 issuppressed.

When the glass transition temperature of the adhesive layer 3 is 100° C.or higher, remaining of the adhesive layer 3 to the lead frame and thesealing material can be suppressed. Furthermore, softening of theadhesive layer 3 by the heat in the wire bonding step can be suppressed,and the occurrence of defective joining of the wire can be reduced. Inaddition, softening of the adhesive layer 3 caused by the heat in thesealing step can be suppressed, and the occurrence of inconvenience thatthe sealing material penetrates between the lead frame and the adhesivelayer 3 can be suppressed. When the glass transition temperature of theadhesive layer 3 is 300° C. or lower, softening of the adhesive layer 3at the time of adhesion is sufficiently suppressed. Furthermore, asufficient peel strength at a peeling angle of 90° between the adhesivefilm 1 and the lead frame at normal temperature (for example, 25° C.)can be secured.

The glass transition temperature of the adhesive layer 3 can be measuredby using a thermomechanical analysis apparatus (manufactured by SeikoInstruments Inc.: SSC5200 type). The measurement conditions can be setto, for example, a tensile mode at a distance between chucks of 10 mm, atemperature range of 30° C. to 300° C., and a rate of temperatureincrease of 10° C./min.

The 5% weight reduction temperature of the adhesive layer 3 may be 300°C. or higher, may be 350° C. or higher, or may be 400° C. or higher.When the 5 weight % reduction temperature of the adhesive layer 3 is300° C. or higher, outgases caused by the heat at the time of stickingthe adhesive film 1 to the lead frame and the heat in the wire bondingstep are not likely to be generated, and contamination of the leadframe, the wire, and the like can be suppressed. The 5% weight reductiontemperature can be measured by using a differential thermal balance (forexample, manufactured by Seiko Instruments Inc.: SSC5200 type). Themeasurement conditions can be set to, for example, a rate of temperatureincrease of 10° C./min in an air atmosphere.

The elastic modulus at 230° C. of the adhesive layer 3 is, for example,1 MPa or greater. The elastic modulus at 230° C. of the adhesive layer 3may be 3 MPa or greater. In the production process for a semiconductorpackage, the temperature in the wire bonding step (wire bondingtemperature) is not particularly limited; however, the temperature isgenerally about 200 to 260° C. and is approximately 230° C. Therefore,when the elastic modulus at 230° C. of the adhesive layer 3 is 1 MPa orgreater, softening of the adhesive layer 3 caused by the heat in thewire bonding step is suppressed, and the occurrence of defective joiningof the wire can be suppressed. The elastic modulus at 230° C. of theadhesive layer 3 is, for example, 2000 MPa or less. The elastic modulusat 230° C. of the adhesive layer 3 may be 1500 MPa or less or may be1000 MPa or less.

The elastic modulus at 230° C. of the adhesive layer 3 can be measuredby using a dynamic viscoelasticity measuring apparatus (for example,manufactured by UBM: Rheogel-E4000). In this case, the measurementconditions can be set to a tensile mode at a distance between chucks of20 mm, sine waves, a frequency of 10 Hz, and a rate of temperatureincrease of 5° C./min.

The method for forming the adhesive layer 3 on the base material layer 2is not particularly limited; however, for example, a method of applyinga resin varnish produced by dissolving a resin in a solvent on thesurface of the base material layer 2 and subsequently removing thesolvent by performing a heating treatment, can be used. Regarding thesolvent, N-methyl-2-pyrrolidone, dimethylacetamide, diethylene glycoldimethyl ether, tetrahydrofuran, cyclohexanone, methyl ethyl ketone,dimethylformamide, and the like can be used. A method of applying aprecursor varnish obtained by dissolving a precursor of a resin in asolvent on the surface of the base material layer 2 and subsequentlyremoving the solvent by performing a heating treatment, can also beused. When the resin that constitutes the adhesive layer 3 is apolyimide resin, the precursor is, for example, polyamic acid.

The temperature of the heating treatment may be different between thecase where a resin varnish is used and the case where a precursorvarnish is used. In the case of a resin varnish, the temperature of theheating treatment may be any temperature at which the solvent can beremoved. In the case of a precursor varnish, the temperature of theheating treatment may be equal to or higher than the glass transitiontemperature of the adhesive layer 3 in order to form a resin from theprecursor (for example, imidization).

The method of applying a resin varnish or a precursor varnish on thesurface of the base material layer 2 is not particularly limited;however, for example, roll coating, reverse roll coating, gravurecoating, bar coating, comma coating, die coating, or reduced pressuredie coating can be used. Furthermore, the resin varnish or the precursorvarnish may be applied on the surface of the base material layer 2 byimmersing the base material layer 2 in the resin varnish or theprecursor varnish.

As shown in FIG. 2 , the adhesive film 1 may be configured to have threelayers by further including a non-adhesive layer 4 on the other surfaceside of the base material layer 2 (opposite surface side of the adhesivelayer 3). The non-adhesive layer 4 is a resin layer that substantiallydoes not have adhesiveness (or pressure-sensitive adhesiveness) to thelead frame at 0° C. to 270° C.

For the formation of the non-adhesive layer 4, for example, athermoplastic resin or a thermosetting resin can be used. Regarding thethermoplastic resin, for example, a resin having an amide group, anester group, an imide group, or an ether group may be mentioned. Thethermoplastic resin may be an aromatic polyetheramideimide obtainable byreacting 1 mol of the above-mentioned base component and 0.95 to 1.05mol or 0.98 to 1.02 mol of the above-mentioned acid component.

Examples of the thermosetting resin include an epoxy resin, a phenolresin, and a bismaleimide resin (for example, a bismaleimide resinhaving bis(4-maleimidophenyl)methane as a monomer). A thermoplasticresin and a thermosetting resin may be used as a mixture. In the case ofusing a thermoplastic resin and a thermosetting resin in combination,the amount of the thermosetting resin may be 5 to 100 parts by mass ormay be 20 to 70 parts by mass with respect to 100 parts by mass of thethermoplastic resin.

The non-adhesive layer 4 may contain components other than theabove-described resin. Examples of the other components include a fillerand a coupling agent. When the non-adhesive layer 4 contains a filler asthe other component, the content of the filler may be 1 to 30 parts bymass or may be 5 to 15 parts by mass with respect to 100 parts by massof the resin. When the non-adhesive layer 4 contains a coupling agent asthe other component, the content of the coupling agent may be 1 to 20parts by mass or may be 5 to 15 parts by mass with respect to 100 partsby mass of the resin.

The thickness of the non-adhesive layer 4 is, for example, 10 μm orless. The thickness of the non-adhesive layer 4 may be 9 μm or less, 8μm or less, or 7 μm or less. The thickness of the non-adhesive layer 4is, for example, 1 μm or more. The thickness of the non-adhesive layer 4may be 2 μm or more, 3 μm or more, 4 μm or more, 5 μm or more, or 6 μmor more. The thickness of the non-adhesive layer 4 may be, for example,1 μm or more and 10 μm or less or may be 1 μm or more and 8 μm or less.The ratio of the thickness of the adhesive layer 3 to the thickness ofthe non-adhesive layer 4 may be 1.0 to 2.0 or may be 1.3 to 2.0.

The elastic modulus at 230° C. of the non-adhesive layer 4 is, forexample, 10 MPa or greater. The elastic modulus at 230° C. of thenon-adhesive layer 4 may be 100 MPa or greater or may be 1000 MPa orgreater. When the elastic modulus at 230° C. of the non-adhesive layer 4is 10 MPa or greater, softening of the non-adhesive layer 4 in a stepwhere heat is applied, such as a wire bonding step, can be suppressed,and sticking to the mold, jigs, and the like can be prevented. Theelastic modulus at 230° C. of the non-adhesive layer 4 may be 2000 MPaor less or may be 1800 MPa or less. The elastic modulus at 230° C. ofthe non-adhesive layer 4 can be measured by a method similar to the caseof the elastic modulus at 230° C. of the above-mentioned adhesive layer3.

The peel strength at a peeling angle of 90° between the non-adhesivelayer 4 and the mold as well as the jig at normal temperature (forexample, 25° C.) may be less than 5 N/m or may be 1 N/m or less. Themeasurement of this peel strength is carried out, for example, afterpressure-bonding the non-adhesive layer 4 to a mold made of brass at atemperature of 250° C. and a pressure of 8 MPa for 10 seconds.

The glass transition temperature of the non-adhesive layer 4 is, forexample, 150° C. or higher. The glass transition temperature of thenon-adhesive layer 4 may be 200° C. or higher or may be 250° C. orhigher. When the glass transition temperature of the non-adhesive layer4 is 150° C. or higher, softening of the non-adhesive layer 4 in a stepof adhering a semiconductor element to a die pad, a wire bonding step, asealing step, a step of peeling off the adhesive film 1 from a sealedbody, and the like can be suppressed. Furthermore, sticking of thenon-adhesive layer 4 to the mold and jigs can be suppressed. The glasstransition temperature of the non-adhesive layer 4 may be 350° C. orlower or may be 300° C. or lower.

The method for forming the non-adhesive layer 4 on the base materiallayer 2 is not particularly limited; however, as in the case of theabove-mentioned adhesive layer 3, a method of applying a resin varnishor a precursor varnish on the base material layer 2 can be employed.When a thermosetting resin is used as a constituent material of thenon-adhesive layer 4, or when a thermoplastic resin and a thermosettingresin are used in combination, the thermosetting resin can be cured by aheating treatment after application to adjust the elastic modulus of thenon-adhesive layer 4 to 10 MPa or greater. This heating treatment may becarried out simultaneously with removal of the solvent or imidization ormay be carried out separately therefrom.

When the non-adhesive layer 4 such as described above is provided on thebase material layer 2, the warpage of the adhesive film 1 caused by thevolume reduction of the adhesive layer 3 can be canceled by the volumereduction of the non-adhesive layer 4 at the time of solvent removal,and shrinkage of the non-adhesive layer 4 at the time of imidization ofthe non-adhesive layer 4, curing of the thermosetting resin, and thelike.

[Adhesive Film Production Apparatus]

Next, the adhesive film production apparatus used for the production ofthe adhesive film 1 will be described in detail.

FIG. 3 is a schematic perspective view illustrating an embodiment of theadhesive film production apparatus. In FIG. 3 , the right-to-leftdirection is designated as the horizontal direction, and the up-to-downdirection is designated as the vertical direction. The adhesive filmproduction apparatus 11 shown in the same diagram is configured to be anapparatus that cuts a plurality of adhesive films 1 from a raw film B ofan adhesive film 1 and winding each of the cut adhesive films 1 to formreel bodies R. As shown in FIG. 3 , the adhesive film productionapparatus 11 includes a feeding roller 12, a cutting part 13, and aplurality of winding cores 14. Here, the production of an adhesive film1 having a two-layer configuration as shown in FIG. 1 will be describedas an example.

The feeding roller 12 is a portion that continuously feeds out the rawfilm B of the adhesive film 1. On the feeding roller 12, as shown inFIG. 4 , the raw film B of the adhesive film 1 is wound around such thatthe adhesive layer 3 faces outward. That is, on the feeding roller 12,the raw film B of the adhesive film 1 is wound around such that theadhesive layer 3 bends in an arc. The raw film B of the adhesive film 1continuously paid out from the feeding roller 12 is horizontallyconveyed toward the cutting part 13 at a predetermined speed.

The cutting part 13 is a portion that cuts out a plurality of adhesivefilms 1 at a predetermined width from the raw film B of the adhesivefilm 1. As shown in FIG. 5 , the cutting part 13 has an upper shaft 16and a lower shaft 17 disposed as a pair disposed up and down with theraw film B interposed therebetween; a plurality of disc-shaped upperblades 18 provided on the upper shaft 16; and a plurality of disc-shapedlower blades 19 provided on the lower shaft 17. In the embodiment ofFIG. 5 , the upper blades 18 face the adhesive layer 3, and the lowerblades 19 face the base material layer 2. The upper blades 18 and thelower blades 19 are in a state in which, for example, the side surfacesof the blade tips are in sliding contact with each other, and the rawfilm B is cut by a shear cutting method. The widths of the plurality ofadhesive films 1 cut by the cutting part 13 are adjusted by changing thedistances in the axial direction between the upper blades 18 and thelower blades 19. In the present embodiment, a plurality of adhesivefilms 1 having different widths are cut out from the raw film B of theadhesive film 1 by the cutting part 13.

The plurality of winding cores 14 is a portion on which each of theplurality of adhesive films 1 is wound. On the winding core 14, theadhesive film 1 is wound such that the feeding roller 12 and theadhesive layer 3 face outward. The winding cores 14 may be classifiedinto the case where an adhesive film 1 having a two-layer configurationas shown in FIG. 1 is wound, and the case where an adhesive film 1having a three-layer configuration as shown in FIG. 2 is wound. Theplurality of winding cores 14 have a first winding core 14A positionedon a first shaft G1 and a second winding core 14B positioned on a secondshaft G2. The first shaft G1 and the second shaft G2 are positioned atpositions that are at least shifted from each other in the horizontaldirection, and the first winding core 14A and the second winding core14B are alternately disposed in the axial directions.

Here, in the conveyance path of the adhesive film 1 traveling from thecutting part 13 toward the winding cores 14, the number of times of theadhesive layer 3 of the adhesive film 1 bending in a convex manner isequal to or more than the number of times of the adhesive layer 3bending in a concave manner. In the form shown in FIG. 3 , the firstshaft G1 on which the first winding core 14A is positioned is disposedsuch that the conveyance direction of the adhesive film 1 traveling fromthe cutting part 13 toward the first winding core 14A is maintainedhorizontally similarly to the conveyance direction of the raw film B. Onthe other hand, the second shaft G2 on which the second winding core 14Bis disposed below the first shaft G1 such that, as shown in FIG. 3 andFIG. 5 , the adhesive layer 3 of the adhesive film 1 traveling from thecutting part 13 toward the second winding core 14B bends in a convexmanner. As the result, the adhesive film 1 traveling from the cuttingpart 13 toward the first winding core 14A is wound by the first windingcore 14A such that the adhesive layer 3 bends neither in a convex mannernor in a concave manner, and the adhesive film 1 traveling from thecutting part 13 toward the second winding core 14B is wound by thesecond winding core 14B such that the adhesive layer 3 bends only in aconvex manner.

Furthermore, each of the first winding core 14A and the second windingcore 14B has a width W2 larger than a width W1 of the adhesive film 1 asan object of winding, as shown in FIG. 6 . As a result, in a reel body Robtained by winding the adhesive film 1 on each of the first windingcore 14A and the second winding core 14B, an edge part 14 a of thewinding core 14 protrudes from a side surface 21 a of a rolled body 21of the adhesive film 1. As an example, when the width W1 of the adhesivefilm 1 as an object of winding is 50 mm or more and less than 55 mm, thewidth W2 of the winding core 14 for winding this adhesive film can beset to 55 mm. Furthermore, in the example of FIG. 6 , the centralposition in the axial direction of the winding core 14 is in a shiftedstate with respect to the central position in the width direction of theadhesive film 1. As a result, in the reel body R, the edge part 14 a ofthe winding core 14 protrudes only from one side surface 21 a in therolled body 21 of the adhesive film 1, and the other side surface 21 ais flush with the edge part 14 a of the winding core 14.

Winding tension is applied to the raw film B and the plurality ofadhesive films 1 extending from the feeding roller 12 through thecutting part 13 to the winding cores 14. For the impartment of thewinding tension to the raw film B and the plurality of adhesive films 1,tension rollers may be used, or an adjustment mechanism for adjustingthe axial positions of the feeding roller 12 and the winding cores 14may be used. The winding tension to be applied to the raw film B and theplurality of adhesive films 1 is not particularly limited; however, forexample, the winding tension is 60 N/m or more. The winding tension maybe 70 N/m or more or may be 80 N/m or more. The winding tension is, forexample, 150 N/m or less. The winding tension may be 140 N/m or less ormay be 130 N/m or less.

[Method for Producing Adhesive Film]

FIG. 7 is a flow chart showing an embodiment of a method for producingan adhesive film. In the present embodiment, the method for producing anadhesive film is carried out by using the above-described adhesive filmproduction apparatus 11. In this method for producing an adhesive film,first, the raw film B of the adhesive film 1 is continuously paid outfrom the feeding roller (step S01: feeding step). In the feeding step,the raw film B of the adhesive film 1 is wound around the feeding roller12 such that the adhesive layer 3 faces outward. That is, the raw film Bof the adhesive film 1 is wound around the feeding roller 12 such thatthe adhesive layer 3 bends in a convex manner. Then, the raw film B ofthe adhesive film 1 continuously paid out from the feeding roller 12 isconveyed horizontally toward the cutting part 13 at a predeterminedspeed.

Next, the raw film B of the adhesive film 1 is cut out into a pluralityof adhesive films 1 having predetermined widths by the cutting part 13(step S02: cutting step). In the cutting step, a plurality of adhesivefilms 1 having different widths are cut out from the raw film B of theadhesive film 1 by the cutting part 13.

After the plurality of adhesive films 1 are cut out, each of theseadhesive films 1 is wound on each of a plurality of winding cores 14(step S03: winding step). In the winding step, the adhesive film 1traveling from the cutting part 13 toward the second winding core 14B isconveyed such that the adhesive layer 3 bends in a convex manner andthen wound. Furthermore, at the time of winding the adhesive film 1 oneach of the first winding core 14A and the second winding core 14B, thecentral position in the axial direction of the winding core 14 isdisposed to be shifted with respect to the central position in the widthdirection of the adhesive film 1. As a result, the reel body R in whichthe adhesive film 1 is wound on each of the first winding core 14A andthe second winding core 14B is in a state in which the edge part 14 a ofthe winding core 14 protrudes from one side surface 21 a of the rolledbody 21 of the adhesive film 1.

[Operating Effect]

As described above, in the adhesive film production apparatus 11, eachof a plurality of winding cores 14 for winding an adhesive film 1 has awidth larger than the width of the adhesive film 1 as an object ofwinding. As a result, winding of an adhesive film 1 having a smallerwidth than the winding core 14 can be carried out by using winding cores14 having the same width. Therefore, in this adhesive film productionapparatus 11, it is possible to reduce the type of winding cores 14 tobe prepared, and the production cost for the reel bodies R can bereduced. Furthermore, since the edge part 14 a of the winding core 14protrudes from the adhesive film 1 as an object of winding, on theoccasion of using an adhesive film 1 wound around a winding core 14,alignment of the adhesive film 1 is made easier by utilizing theprotruding portion of the winding core 14.

Furthermore, in the adhesive film production apparatus 11, each of theplurality of winding cores 14 is disposed such that the edge part 14 aof this winding core 14 protrudes only on one side in the axialdirection from the adhesive film 1 as an object of winding. In thiscase, on the occasion of using an adhesive film 1 wound around a windingcore 14, for example, alignment of the adhesive film 1 at the time ofmounting the reel body R on an apparatus on the side of use is made mucheasier.

Modification Example

The present disclosure is not limited to the above-describedembodiments. FIG. 8 is a schematic perspective view illustrating anotherembodiment of the adhesive film production apparatus. In the example ofFIG. 3 , the raw film B continuously paid out from the feeding roller 12is conveyed in the horizontal direction toward the cutting part 13;however, as in the case of example of FIG. 8 , a roller 31 that appliestension to the raw film B may be disposed between the feeding roller 12and the cutting part 13, and the raw film B may be caused to bend in aconvex manner by means of this roller 31. It is also acceptable todispose a plurality of rollers similar to the roller 31 and cause theraw film B between the feeding roller 12 and the cutting part 13 to bendmultiple times in a convex manner and in a concave manner. In this case,in the conveyance path of the raw film B traveling from the feedingroller 12 toward the cutting part 13, the number of times of theadhesive layer 3 of the raw film B bending in a convex manner may beequal to or more than the number of times of the adhesive layer 3bending in a concave manner. When the raw film B is caused to bendmultiple times, the final bending (bending on the side closest to thecutting part 13) may be bending in a convex manner.

Furthermore, in the example of FIG. 3 , only the adhesive layer 3 of theadhesive film 1 traveling from the cutting part 13 toward the secondwinding core 14B bends in an arc; however, as in the case of the exampleof FIG. 8 , a roller 32 that applies winding tension to the raw film Bmay be disposed between the feeding roller 12 and the cutting part 13,and the adhesive film 1 may be caused to bend in a convex manner bymeans of this roller 32. It is also acceptable to dispose a plurality ofrollers similar to the roller 32 and cause the raw film B between thecutting part 13 and the winding cores 14 to bend multiple times in aconvex manner and in a concave manner. In this case, in the conveyancepath of the adhesive film 1 traveling from the cutting part 13 towardthe winding cores 14, the number of times of the adhesive layer 3 of theadhesive film 1 bending in a convex manner may be equal to or more thanthe number of times of the adhesive layer 3 bending in a concave manner.When the adhesive film 1 is caused to bend multiple times, the finalbending (bending on the side closest to the winding core 14) may bebending in a convex manner.

In the example of FIG. 8 , the first shaft G1 on which the first windingcore 14A is positioned and the second shaft G2 on which the secondwinding core 14B is positioned are positioned at the same position inthe vertical direction. The first winding core 14A is disposed such thatthe conveyance direction of the adhesive film 1 traveling from thecutting part 13 toward the first winding core 14A bends at anapproximately right angle with respect to the roller 32, and the secondwinding core 14B is disposed such that the conveyance direction of theadhesive film 1 traveling from the cutting part 13 toward the secondwinding core 14B bends at an acute angle with respect to the roller 32.As the result, each of the adhesive film 1 traveling from the cuttingpart 13 toward the first winding core 14A and the adhesive film 1traveling from the cutting part 13 toward the second winding core 14B issuch that the adhesive layer 3 bends only in a convex manner and iswound by a winding core 14.

Furthermore, for example, in the example of FIG. 6 , the edge part 14 aof the winding core 14 protrudes only from one side surface 21 a in therolled body 21 of the adhesive film 1, and the other side surface 21 ais flush with the edge part 14 a of the winding core 14; however, theedge parts 14 a of the winding core 14 may respectively protrude fromone side surface 21 a and the other side surface 21 a in the rolled body21 of the adhesive film 1. That is, the edge part 14 a of the windingcore 14 may protrude on both sides in the axial direction from the sidesurfaces 21 a of the rolled body 21 of the adhesive film 1.

In this case, in the rolled body 21 of the adhesive film 1, the amountof protrusion of the edge part 14 a of the winding core 14 from one sidesurface 21 a and the amount of protrusion of the edge part 14 a of thewinding core 14 from the other side surface 21 a may be equal.Furthermore, the amount of protrusion of the edge part 14 a of thewinding core 14 from one side surface 21 a in the rolled body 21 of theadhesive film 1 may be larger than the amount of protrusion of the edgepart 14 a of the winding core 14 from the other side surface 21 a. Insuch a configuration as well, when an adhesive film 1 wound around awinding core 14 is used, alignment of the adhesive film 1 is made mucheasier. The ratio of the amount of protrusion of the edge part 14 a ofthe winding core 14 from one side surface 21 a with respect to theamount of protrusion of the edge part 14 a of the winding core 14 fromthe other side surface 21 a may be, for example, 0.02 to 5.00 or may be0.04 to 3.00.

REFERENCE SIGNS LIST

1: adhesive film, 2: base material layer, 3: adhesive layer, 11:adhesive film production apparatus, 12: feeding roller, 13: cuttingpart, 14: winding core, 14 a: edge part, B: raw film, R: reel body, W1:width of adhesive film, W2: width of winding core.

1. An adhesive film production apparatus for producing an adhesive filmhaving an adhesive layer on a base material layer, the adhesive filmproduction apparatus comprising: a feeding roller configured tocontinuously feed a raw film of the adhesive film; a cutting partconfigured to cut the raw film of the adhesive film into a plurality ofadhesive films having predetermined widths; and a plurality of windingcores configured to wind each of the plurality of adhesive films,wherein each of the plurality of winding cores has a width larger than awidth of the adhesive film as an object of winding.
 2. The adhesive filmproduction apparatus according to claim 1, wherein each of the pluralityof winding cores is disposed such that an edge part of the winding coreprotrudes only on one side in an axial direction from the adhesive filmas an object of winding.
 3. A reel body obtainable by winding anadhesive film having an adhesive layer on a base material layer around awinding core, wherein the winding core has a width larger than a widthof the adhesive film.
 4. The reel body according to claim 3, wherein anedge part of the winding core protrudes only on one side in an axialdirection from a side surface of a rolled body of the adhesive film. 5.The reel body according to claim 3, wherein edge parts of the windingcore protrudes on both sides in an axial direction from side surfaces ofa rolled body of the adhesive film, and an amount of protrusion on oneside in the axial direction is larger than an amount of protrusion onthe other side.